Multiple JE Approvers

My institution is looking into implementing JE approvals. One thing we can not figure out is what to do if the approver is away from the office. How do we get the notification to go above that approver so they could approve the JE instead of having to wait for the manager to come back to the office? As an example:

user JSmith enters a journal and clicks the approve button

user SFields is the approver for JSmith's journal entries, but they are on vacation for a week.

user JPublic is the approver for SFields' journals.

Is there a way for the notification to either skip SFields and go straight to JPublic or have both SFields and JPublic notified and able to approve JSmith's journal entry?  Thanks for the help.